Especially during the driving or sinking of large-diameter bore holes, drilling fluid is fed to the bore hole during the drilling operation. On the one hand, the drilling fluid serves the purpose of lubricating the drilling tools operating at the heading face or at the bottom of the shaft and of supporting the heading face and the wall of the bore hole. On the other hand, the drilling fluid can also be used to bring dissolved drill cuttings out of the bore hole, for example, by feeding fresh drilling fluid centrally through a hollow drill string in the area of the bottom of the bore hole or in the area of the heading face, thereby producing a flow of drilling fluid, which entrains the dissolved drill cuttings and removes them from the bore hole.
The production of the drilling fluid flow necessary for bringing out the drilled material requires very heavy-duty pumping systems. The pumping capacity of these kinds of pumping systems is generally on the order of a maximum of 3,000 L/min at a maximum pressure of 500 bars.
The prior art describes pumping systems that are distinguished by especially compact construction, since the rotary drive unit of the pumping system that drives the pump unit is installed above the pump unit and is flange-mounted on the upper side of the pump housing. The rotary drive units generally have power ratings of up to 1,700 kW.
In order to be able to transmit this power or the torque delivered by the rotary drive unit to the input shaft of the pump unit, it is well known that both the shaft of the rotary drive and the drive shaft of the pump can be brought out of their respective housings at both ends, so that each shaft has two shaft ends. A sprocket wheel is nonrotatably supported on each shaft end. Accordingly, torque is transmitted by two chains that run parallel to each other.
A disadvantage of pumping systems of this type is the highly complex design necessitated by chains running on both sides, which requires doubling of the parts and especially four shaft bushings with corresponding sealing systems. In addition, the chain drives cause a high noise level during operation.